1. Field of the Invention
The present invention relates to a support plate for an exposure apparatus that exposes a substrate through a liquid, an exposure apparatus having the support plate, and a device manufacturing method using the exposure apparatus.
2. Description of the Related Art
Exposure apparatuses that expose a wafer to a pattern of a reticle are used for manufacturing devices such as semiconductor devices and liquid crystal devices.
Miniaturization of devices requires improvement in the resolving power of projection optical systems of exposure apparatuses. As a means for improving the resolving power, an immersion exposure technique has attracted attention. The immersion exposure technique is a technique in which the space between the last lens of a projection optical system and a wafer is filled with a liquid and the wafer is exposed through the liquid. Exposure apparatuses using the immersion exposure technique are called immersion exposure apparatuses.
Immersion exposure apparatuses mostly use a so-called local fill method in which not the entire wafer surface but only part of the wafer surface including an exposed part is immersed in a liquid.
In the immersion exposure apparatuses using the local fill method, a liquid is supported by a wafer when the central part of the wafer is exposed, whereas the liquid outside the wafer is not supported when the periphery of the wafer is exposed. To solve this problem, WO 05/055296 proposes to provide a support plate on the wafer stage of an immersion exposure apparatus. The support plate is disposed around the periphery of a wafer and supports a liquid outside the wafer. Japanese Patent Laid-Open No. 2006-319065 proposes to form a texture (liquid-repellent structure) on the surface of a support plate to make the surface of the support plate liquid-repellent.
To make the surface of a support plate liquid-repellent, it is necessary to form a fine texture the pitch of which is 500 μm or less. Forming such a texture requires many processes. Therefore, the cost of a support plate in the entire surface of which a texture is formed is high.
When a support plate is detachably attached to a wafer stage, the texture on the surface of the support plate is likely to be broken when the support plate is attached or detached.